Measurement of the ttbar Production Cross Section using the Semileptonic Final States in pp Collisions at √s=7 TeV with 35.3 pb⁻¹ of ATLAS Data

Persistent Link:
http://hdl.handle.net/10150/202932
Title:
Measurement of the ttbar Production Cross Section using the Semileptonic Final States in pp Collisions at √s=7 TeV with 35.3 pb⁻¹ of ATLAS Data
Author:
Lei, Xiaowen
Issue Date:
2011
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
A measurement of the production cross section for top quark pairs (tt) in pp collisions at √s = 7 TeV is presented using data recorded with the ATLAS experiment at the Large Hadron Collider in 2010. Events are selected in the tt semileptonic decay channel by requiring a single lepton (electron e or muon μ), large missing transverse energy and at least four jets. In a data sample of 35:3 pb⁻¹, 396 e + jets events and 653 μ + jets events are observed. A multivariate top likelihood is built from four variables including a b-tagging variable. A fit to the top likelihood distribution is employed to extract the tt cross section separately in the e+ jets and μ + jets channel. A combined fit to the top likelihood distribution in both channels is employed to extract a combined cross section. The tt cross section, assuming a top mass of 172.5 GeV, is found to be: e + jets channel: σ(u) = 164.4^+16.2(-15.4)(stat)^31.2(-36.2)(syst)^5.8(-5.4)(lumi) pb; μ + jets channel: σ(u) = 167.8^+1.3.9(-13.4)(stat)^3.9(-34.8)(syst)^5.9(-5.5)(lumi) pb; e + jets and μ + jets channel combined: σ(u) = 166.4^+10.5(-10.2)(stat)^31.7(-33.6)(syst)^5.9(-5.5)(lumi) pb The measurement agrees with approximate NNLO perturbative QCD calculations.
Type:
text; Electronic Dissertation
Keywords:
Physics
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Physics
Degree Grantor:
University of Arizona
Advisor:
Johns, Kenneth

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleMeasurement of the ttbar Production Cross Section using the Semileptonic Final States in pp Collisions at √s=7 TeV with 35.3 pb⁻¹ of ATLAS Dataen_US
dc.creatorLei, Xiaowenen_US
dc.contributor.authorLei, Xiaowenen_US
dc.date.issued2011-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractA measurement of the production cross section for top quark pairs (tt) in pp collisions at √s = 7 TeV is presented using data recorded with the ATLAS experiment at the Large Hadron Collider in 2010. Events are selected in the tt semileptonic decay channel by requiring a single lepton (electron e or muon μ), large missing transverse energy and at least four jets. In a data sample of 35:3 pb⁻¹, 396 e + jets events and 653 μ + jets events are observed. A multivariate top likelihood is built from four variables including a b-tagging variable. A fit to the top likelihood distribution is employed to extract the tt cross section separately in the e+ jets and μ + jets channel. A combined fit to the top likelihood distribution in both channels is employed to extract a combined cross section. The tt cross section, assuming a top mass of 172.5 GeV, is found to be: e + jets channel: σ(u) = 164.4^+16.2(-15.4)(stat)^31.2(-36.2)(syst)^5.8(-5.4)(lumi) pb; μ + jets channel: σ(u) = 167.8^+1.3.9(-13.4)(stat)^3.9(-34.8)(syst)^5.9(-5.5)(lumi) pb; e + jets and μ + jets channel combined: σ(u) = 166.4^+10.5(-10.2)(stat)^31.7(-33.6)(syst)^5.9(-5.5)(lumi) pb The measurement agrees with approximate NNLO perturbative QCD calculations.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectPhysicsen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplinePhysicsen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorJohns, Kennethen_US
dc.contributor.committeememberCheu, Elliotten_US
dc.contributor.committeememberFang, Li-Zhien_US
dc.contributor.committeememberSu, Shufangen_US
dc.contributor.committeememberWing, Williamen_US
dc.contributor.committeememberJohns, Kennethen_US
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